solve for i
399=59.88*(1-((1/(1+i)^(1/12))^12)/(1+i)^(1/12)-1)*(1+i)^(1/12)
You asked:
Solve the equation \[399 = 59.88 \cdot \left(1 - \frac{{\left( \frac{1}{{\left( 1 + i \right)}^{\frac{1}{12}}} \right)}^{12}}{{\left( 1 + i \right)}^{\frac{1}{12}}} - 1\right) \cdot {\left( 1 + i \right)}^{\frac{1}{12}}\] for the unknown \(i\).